Rotating electrical machine

ABSTRACT

A relay conductor of a rotating electrical machine is provided with: a coil connector that is connected to a coil on one side of a rotating shaft and further to the outside in the radial direction than the coil; a power line connector that is connected to an external power line on the other side of the rotating shaft; and relays that extend in the axial direction of the rotating shaft, and link the coil connector and the power line connector. At least a portion of the power line connector is positioned closer to the inner diameter side of the rotating electrical machine than the outer peripheral surface of a stator.

TECHNICAL FIELD

The present invention relates to a rotary electric machine (rotatingelectrical machine) having a wiring arrangement that makes it possibleto reduce the size of the rotary electric machine in a radial direction.

BACKGROUND ART

According to Japanese Laid-Open Patent Publication No. 2009-017667(hereinafter referred to as “JP 2009-017667 A”), three feeder terminals63 of a motor 1 are disposed radially outward of a stator holder 11 (seeFIGS. 2 and 3). An electric power line, which connects the motor 1 to aninverter and a non-illustrated electric storage device, is connected toeach of the feeder terminals 63.

SUMMARY OF INVENTION

If the feeder terminals 63 are disposed radially outward of the statorholder 11, as disclosed in JP 2009-017667 A, the radial dimension of themotor 1 is increased, because the feeder terminals 63 must be connectedto the electric power lines radially outward of the stator holder 11.

The present invention has been made in view of the aforementionedproblem. An object of the present invention is to provide a rotaryelectric machine that can be reduced in size in a radial direction.

According to the present invention, a rotary electric machine ischaracterized by a stator with coils wound thereon, a housing thathouses the stator therein, and a junction conductor electrically joiningthe coils and external electric power lines, which are disposed outsideof the housing, to each other. The junction conductor includes coiljoints connected to the coils on one side of a rotational shaft of therotary electric machine radially outward of the coils, electric powerline joints connected to the external electric power lines on anotherside of the rotational shaft, and a junction extending in an axialdirection of the rotational shaft and coupling the coil joints and theelectric power line joints to each other. Further, at least a portion ofthe electric power line joints is positioned radially inward of an outercircumferential surface of the stator with respect to the rotaryelectric machine.

According to the present invention, the electric power line joints areshifted from the stator in the axial direction, and are positionedradially inward of the outer circumferential surface of the stator.Therefore, rather than being positioned radially outward of the outercircumferential surface of the stator, the dimension of the rotaryelectric machine along the radial direction thereof is reduced by theextent to which the external electric power line joints are positionedradially inward of the outer circumferential surface of the stator.

The junction conductor may include coil-side conductors including thecoil joints, and electric power line-side conductors including theelectric power line joints, the electric power line-side conductorsbeing separate from the coil-side conductors. The coil-side conductorsand the electric power line-side conductors are connected tointermediate joints, which are positioned radially outward of the outercircumferential surface of the stator.

When the stator is assembled in an axial direction on the housing, if aportion of the electric power line joints is positioned radially inwardof the outer circumferential surface of the stator, it may be difficultto work from the axial direction on the external electric power linejoints. According to the above structure, however, the electric powerline-side conductors and the external electric power lines may beconnected together mutually, thereby making up the external electricpower line joints. Then, the coil-side conductors and the electric powerline-side conductors may be connected in order to make up theintermediate joints, so that the coils and the electric power lines canbe connected to each other. Consequently, it is easier to assemble thejunction conductor.

The coil joints and the intermediate joints may have respectiveportions, which are staggered mutually on circumferential planes havingthe same radius as viewed axially from the rotational shaft. Such aconfiguration prevents the rotary electric machine from becomingincreased in dimension along the radial directions. In addition, sincethe intermediate joints can be worked on along the axial direction, itis easier to assemble the coil-side conductors.

The coils may have coil ends that project radially outward with respectto the rotary electric machine, and the coil joints may be made up ofthe junction conductor and the coil ends, which are connected to eachother. The junction conductor may include bent plate-like members. Thebent plate-like members may further include first planar portionsincluding the coil joints, the first planar portions being disposedalong radial and circumferential directions of the rotary electricmachine, and second planar portions coupled to the first planarportions, the second planar portions extending along axial and radialdirections radially outward of the outer circumferential surface of thestator.

With the above arrangement, each of the first planar portions and thesecond planar portions lies perpendicular to the outer circumferentialsurface of the stator. Therefore, the plate-like members can easily bespaced from the outer circumferential surface of the stator, and it ispossible to prevent degradation of the insulation between the plate-likemembers (junction conductor) and the outer circumferential surface ofthe stator. Further, since the second planar portions extend in both theaxial direction and the radial direction, the plate-like members(junction conductor) are prevented from becoming increased in dimensionalong the circumferential direction.

The rotary electric machine may be coupled to one end of a speedreducer, and the electric power line joints may be disposed closer tothe speed reducer than the stator in an axial direction of the rotaryelectric machine. Consequently, the external electric power line jointscan be installed while taking into consideration the positionalrelationship between the external electric power line joints and the endof the speed reducer. Thus, depending on the layout, the dimension ofthe rotary electric machine can be reduced along the axial direction.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a fragmentary cross-sectional view of a vehicle, especially acooling system thereof, in which there is incorporated a motor thatserves as a rotary electric machine according to an embodiment of thepresent invention;

FIG. 2 is an enlarged fragmentary cross-sectional view showing flows ofan oil coolant in the motor;

FIG. 3 is a fragmentary perspective view, partially cut away, of anelectric power system of the vehicle;

FIG. 4 is a fragmentary cross-sectional view taken along line IV-IV ofFIG. 3;

FIG. 5 is a perspective view of a side cover that functions as a portionof the cooling system;

FIG. 6 is a plan view, which is illustrated in a simplified form,showing the positions of through holes in a motor rotor;

FIG. 7 is a perspective view of a joint between a motor stator and ajunction conductor;

FIG. 8 is a perspective view showing a positional relationship betweenthe motor stator and the junction conductor;

FIG. 9 is a perspective view of a fusing member;

FIG. 10 is a front elevational view showing a positional relationshipbetween fusing members and a terminal base;

FIG. 11 is a view showing a stator that is illustrated in FIG. 3 of JP2009-017667 A;

FIG. 12 is a first perspective view of the terminal base with bus barsassembled thereon;

FIG. 13 is a second perspective view of the terminal base with the busbars assembled thereon;

FIG. 14 is a view showing a positional relationship between a motorhousing and the terminal base with the bus bars assembled thereon;

FIG. 15 is an exploded perspective view of the terminal base and the busbars;

FIG. 16 is a perspective view of a second cover (insulating cover) withthe bus bars assembled thereon;

FIG. 17 is a perspective view of the insulating cover;

FIG. 18 is a cross-sectional view, taken along line XVIII-XVIII of FIG.16, of the insulating cover, at a position where oil discharge ports arenot present; and

FIG. 19 is a fragmentary cross-sectional view, taken along line XIX-XIXof FIG. 16, of the insulating cover, at a position where an oildischarge port is present.

DESCRIPTION OF EMBODIMENTS A. Embodiment 1. Description of OverallArrangement

[1-1. Overall Arrangement]

FIG. 1 is a fragmentary cross-sectional view of a vehicle 10, especiallya cooling system (coolant supply unit) thereof, which incorporates amotor 12 as a rotary electric machine according to an embodiment of thepresent invention. FIG. 2 is an enlarged fragmentary cross-sectionalview showing flows of an oil coolant 42 in the motor 12. In FIG. 2, thethick arrows represent flows of the oil coolant 42. FIG. 3 is afragmentary perspective view, partially cut away, of an electric powersystem of the vehicle 10. FIG. 4 is a fragmentary cross-sectional viewtaken along line IV-IV of FIG. 3. It should be noted that, forfacilitating understanding of the present invention, FIGS. 1 and 2 arecross-sectional views taken along line I-I of FIG. 6, to be describedlater. Further, a side cover 30 (to be described later) in FIGS. 1 and 2is shown in cross section (taken along line I-I of FIG. 5) through allof an inlet hole 32 and first through third outlet holes 36, 38, 40, tobe described later (see FIG. 5).

As shown in FIG. 1, the vehicle 10 has a speed reducer 14, which servesas a gear mechanism, in addition to the motor 12. A portion of the speedreducer 14 is disposed in the motor 12.

The motor 12 serves as a drive source for generating a drive force F forthe vehicle 10. The motor 12 comprises a three-phase AC brushless motorfor generating the drive force F for the vehicle 10 based on electricpower supplied from a non-illustrated battery through a non-illustratedinverter. The motor 12 also regenerates electric power (regenerativeelectric power Preg) [W] in a regenerative mode, and outputs theregenerative electric power Preg to the battery in order to charge thebattery. The regenerative electric power Preg may be output to a 12-voltsystem or a non-illustrated accessory device.

As shown in FIGS. 1 through 4, the motor 12 has a motor rotor 20(hereinafter also referred to as a “rotor 20”), a motor stator 22(hereinafter also referred to as a “stator 22”), a resolver rotor 24, aresolver stator 26, a motor housing 28, and the side cover 30. Theresolver rotor 24 and the resolver stator 26 jointly make up a resolver31.

[1-2. Cooling System]

(1-2-1. Side Cover 30)

FIG. 5 is a perspective view of the side cover 30, which functions as aportion of the cooling system. As shown in FIGS. 1, 2, and 5, the sidecover 30 has a single inlet hole 32, a flow passage 34, a single firstoutlet hole 36, a single second outlet hole 38, and a plurality of thirdoutlet holes 40. The first through third outlet holes 36, 38, 40 aresupplied with an oil coolant 42 from a non-illustrated pump, which maybe an electric pump or a mechanical pump.

As shown in FIGS. 1, 2, and 5, according to the present embodiment, theoil coolant 42 is ejected or discharged from the side cover 30 towardthe rotor 20 and the stator 22.

More specifically, the first outlet hole 36 ejects or discharges the oilcoolant 42 primarily toward a rotational shaft 50 of the rotor 20. Thesecond outlet hole 38 ejects or discharges the oil coolant 42 primarilytoward a tubular member 52 of the rotor 20. The third outlet hole 40ejects or discharges the oil coolant 42 primarily toward the stator 22.Each of the outlet holes 36, 38, 40 is in the form of a nozzle forejecting or discharging the oil coolant 42.

(1-2-2. Motor Rotor 20)

(1-2-2-1. Rotational Shaft 50)

As shown in FIGS. 1 and 2, the rotational shaft 50 of the rotor 20 hasan axial opening 53 for supplying the oil coolant 42 to the inside ofthe rotational shaft 50, a single first axial flow passage 54 thatextends along axial directions X1, X2 (see FIG. 1), and a plurality ofsecond axial flow passages 56, which establish fluid communication alongradial directions R1, R2 (see FIG. 6) of the motor 12 between the firstaxial flow passage 54 and the outside of the rotational shaft 50.

The oil coolant 42, which is supplied from the first outlet hole 36 ofthe side cover 30, is guided through the first axial flow passage 54into the second axial flow passages 56, and then is discharged throughthe second axial flow passages 56 from the rotational shaft 50. Thedischarged oil coolant 42 is supplied to the inside of the rotor 20 orto a portion of the speed reducer 14.

(1-2-2-2. Tubular Member 52)

(1-2-2-2-1. General)

As shown in FIG. 2, etc., the rotor 20 has, in addition to therotational shaft 50, a bottomed tubular member 52, a rotor core 60, anda rotor yoke 62.

The tubular member 52 includes a bottom wall 70 fixed to the outercircumferential surface of the rotational shaft 50 near the side cover30, and a side wall 72 that extends in the axial direction X2 from theouter edge of the bottom wall 70. The side wall 72 opens remotely fromthe bottom wall 70, i.e., the side wall 72 has an opening 74 remote fromthe bottom wall 70. The speed reducer 14 has a planet gear 76 disposedin the tubular member 52.

(1-2-2-2-2. Bottom Wall 70)

As shown in FIG. 2, the bottom wall 70 includes a base 80, a firstprotrusive wall 82, and a second protrusive wall 84. The base 80 extendsalong the radial direction R1. The base 80 has a plurality of throughholes 86 defined in a portion thereof. The through holes 86 extend alongthe axial directions X1, X2 through the bottom wall 70 (base 80).

FIG. 6 is a plan view showing the positions of the through holes 86 inthe motor rotor 20, which is illustrated in a simplified form. As shownin FIG. 6, according to the present embodiment, there are four throughholes 86, which are spaced at equal intervals. The oil coolant 42, whichis ejected from the side cover 30 toward the bottom wall 70, is suppliedthrough the through holes 86 to the inside of the tubular member 52.

The first protrusive wall 82 projects toward the side cover 30 (alongthe direction X1) from a portion positioned radially outward (along thedirection R1) of the through holes 86. The first protrusive wall 82 hasan annular shape. For this reason, if the oil coolant 42, which isejected or discharged from the side cover 30 toward the bottom wall 70during rotation of the rotor 20, does not enter the through holes 86directly, then the oil coolant 42 remains in an inner circumferentialregion of the first protrusive wall 82, i.e., a region surrounded by thebase 80 and the first protrusive wall 82, under centrifugal forces thatact on the oil coolant 42. Stated otherwise, the base 80 and the firstprotrusive wall 82 jointly provide a reservoir 88 for the coolant.Therefore, even if the oil coolant 42 does not enter the through holes86 directly, the oil coolant 42 remains in the reservoir 88 andthereafter is supplied through the through holes 86 to the inside of thetubular member 52.

The first protrusive wall 82 has a portion that overlaps with the axialopening 53 of the rotational shaft 50, as viewed along the radialdirections R1, R2 of the rotor 20. Therefore, the oil coolant 42, whichoverflows the first axial flow passage 54 through the axial opening 53,remains in the inner circumferential region of the first protrusive wall82 under centrifugal forces or by gravity, and thereafter, the oilcoolant 42 is supplied through the through holes 86 to the inside of thetubular member 52. Consequently, the oil coolant 42, which flows overthe first axial flow passage 54 through the axial opening 53, can beused to cool the rotor core 60 efficiently.

In addition, as shown in FIG. 2, the first protrusive wall 82 has agreater-diameter portion 90, which is progressively greater in diameterin a direction from the side cover 30 toward the base 80 of the bottomwall 70, i.e., in the direction X2. The greater-diameter portion 90makes it easy for the reservoir 88 to be formed radially inward of thefirst protrusive wall 82, i.e., in the direction R2, thereby minimizingthe amount of oil coolant 42 that does not enter into the tubular member52 after being supplied radially inward of the first protrusive wall 82,i.e., in the direction R2. In FIG. 2, the first protrusive wall 82 isshown as being increased in diameter in both radial inward and radialoutward directions. However, even if the first protrusive wall 82 isincreased in diameter in the radial inward direction only, the firstprotrusive wall 82 is capable of operating in the aforementioned mannerto offer the advantages described above.

The resolver rotor 24, i.e., the rotor of a rotary sensor, is fixed to aradial outer surface of the first protrusive wall 82, i.e., a surfacethereof that faces in the direction R1. Therefore, the first protrusivewall 82 functions both to provide the reservoir 88 for the oil coolant42, and to retain the resolver rotor 24. Consequently, the motor 12 canbe simpler in structure than if a member for retaining the resolverrotor 24 were provided separately from the first protrusive wall 82.

As shown in FIG. 2, the second protrusive wall 84 projects toward theopening 74 (along the direction X2 in FIG. 2) from a portion positionedradially outward (along the direction R1) of the through holes 86. Thesecond protrusive wall 84 has an annular shape. A distal end of thesecond protrusive wall 84 overlaps with a portion of the planet gear 76,as viewed along a radial outward direction of the rotor 20 (along thedirection R1). Therefore, the oil coolant 42, which is guided by thesecond protrusive wall 84, is supplied to a portion of the planet gear76 when the oil coolant 42 is discharged under centrifugal forces in aradial outward direction (along the direction R1).

(1-2-2-2-3. Side Wall 72)

As shown in FIGS. 1 and 2, the rotor core 60 and the rotor yoke 62 arefixed to a radial outer surface (which faces in the direction R1) of theside wall 72 of the tubular member 52. As described above, the oilcoolant 42 is supplied from the side cover 30 to the inside of thetubular member 52 through the rotational shaft 50 or the bottom wall 70of the tubular member 52. Thereafter, as the oil coolant 42 moves alongthe side wall 72 while the rotor 20 rotates, the oil coolant 42 coolsthe rotor core 60.

The oil coolant 42, which has reached the side wall 72, moves along theside wall 72 into the opening 74 from which the oil coolant 42 isdischarged. Thereafter, the oil coolant 42, which is discharged from theopening 74, is pooled on the bottom (not shown) of the motor housing 28,whereupon the oil coolant 42 is ejected or discharged again from theside cover 30 toward the rotor 20 or the stator 22 by the pump. Heatfrom the oil coolant 42 may undergo heat transfer by a cooler or awarmer, not shown, before the oil coolant 42 is ejected or dischargedagain.

(1-2-3. Motor Stator 22)

The oil coolant 42, which is supplied from the third outlet holes 40 ofthe side cover 30, passes through the stator 22 while cooling variousparts of the stator 22, and drops onto the bottom of the motor housing28.

As will be described in detail later, even if the oil coolant 42 entersa second cover 182 (insulating cover) upon moving through the stator 22,the oil coolant 42 is discharged through oil discharge ports 190 (seeFIGS. 16, 17, and 19).

As shown in FIG. 2, etc., the resolver stator 26 is disposed on themotor stator 22 radially outward of the resolver rotor 24 along thedirection R1. The resolver stator 26 produces an output signal dependingon the rotational angle of the resolver rotor 24. Therefore, theresolver 31 is capable of detecting the rotational angle of the motorrotor 20.

[1-3. Electric Power System]

(1-3-1. General)

As described above, FIG. 3 is a fragmentary perspective view, partiallycut away, of the electric power system of the vehicle 10 in which themotor 12, which serves as a rotary electric machine according to thepresent embodiment, is incorporated. FIG. 4 is a fragmentarycross-sectional view taken along line IV-IV of FIG. 3.

In addition to the rotor 20 and the stator 22, the electric power systemof the motor 12 according to the present embodiment includes a harness100 (external electric power lines 102) and a junction conductor 104.

(1-3-2. Motor Stator 22)

FIG. 7 is a perspective view of a joint between the motor stator 22 andthe junction conductor 104. FIG. 8 is a perspective view showing apositional relationship between the motor stator 22 and the junctionconductor 104.

The stator 22 includes coils 112 in a plurality of phases (phase U,phase V, phase W) wound on stator cores 110 with insulating members 111interposed therebetween. As shown in FIG. 7, the coils 112 haverespective ends bundled into coil ends 114 in the respective phases. Asshown in FIG. 7, the coil ends 114 project radially outward (along thedirection R1). Reference should also be made to FIG. 7 of JP 2009-017667A, which provides a description of the manner in which the ends of thecoils 112 are bundled in the respective phases.

As shown in FIGS. 3, 4, 7, and 8, the stator cores 110 are housed in astator holder 116 (stator housing), which is disposed on a radialoutward side (along the direction R1).

(1-3-3. Harness 100 (External Electric Power Lines 102)

The harness 100 includes external electric power lines 102 in the pluralphases (phase U, phase V, phase W). The external electric power lines102 refer to electric power lines, which connect the motor 12 and thenon-illustrated inverter outside of the motor housing 28. As shown inFIG. 4, terminals 120 of the external electric power lines 102 areconnected to the junction conductor 104. According to the presentinvention, joints (external electric power line joints 122) between theterminals 120 and the junction conductor 104 are disposed radiallyinward (along the direction R2) of the outer circumferential surface ofthe stator 22 (and the outer circumferential surface of the statorholder 116). Therefore, the overall dimension of the motor 12 along thedirections R1, R2 is small. The external electric power line joints 122are positioned closer to the speed reducer 14 than the stator 22 alongthe axial directions X1, X2.

(1-3-4. Junction Conductor 104)

The junction conductor 104 serves to electrically join (connect) thecoils 112 and the external electric power lines 102. The junctionconductor 104 comprises fusing members 130 (coil-side conductors) in therespective phases, bus bars 132 a through 132 c (external electric powerline-side conductors) in the respective phases, and a terminal base 134.The fusing members 130 and the bus bars 132 a through 132 c jointly makeup a junction.

(1-3-4-1. Fusing Members 130)

FIG. 9 is a perspective view of a fusing member 130. FIG. 10 is a frontelevational view showing a positional relationship between the fusingmembers 130 and the terminal base 134. As shown in FIGS. 7 and 9, etc.,each of the fusing members 130 is in the form of a bent plate.

More specifically, the fusing member 130 includes a coil connectingpanel 140, a terminal base connecting panel 142, and an intermediatepanel 144 disposed between the coil connecting panel 140 and theterminal base connecting panel 142.

As shown in FIG. 9, the coil connecting panel 140 has an opening 146defined therein for insertion of the coil ends 114. After the coil ends114 have been inserted in the opening 146, the tip end of the coilconnecting panel 140 is biased in the direction indicated by the arrowA1 in FIG. 9 so as to close the opening 146, and the coil ends 114 andthe coil connecting panel 140 are joined by being crimped with heat (seeFIG. 7, etc.). The joints between the coil ends 114 and the coilconnecting panel 140 will hereinafter be referred to as “coil joints147”.

As shown in FIGS. 3, 7, and 10, the terminal base connecting panels 142are fastened to the terminal base 134 by bolts 148 and nuts 150 (seealso FIG. 15).

As seen from FIGS. 3, 7, and 10, the coil connecting panel 140, theterminal base connecting panel 142, and the intermediate panel 144according to the present embodiment lie in directions (the directionsR1, R2) perpendicular to the outer circumferential surface of the stator22 (or the stator holder 116).

More specifically, the coil connecting panel 140 and the terminal baseconnecting panel 142 are disposed in circumferential directions (thedirections C1, C2 in FIG. 10) and radial directions (the directions R1,R2 in FIG. 10). The thicknesswise directions of the coil connectingpanel 140 and the terminal base connecting panel 142 are disposedparallel to the axial directions X1, X2 and are not oriented toward theouter circumferential surface of the stator 22. The intermediate panel144 is disposed along axial directions (the directions X1, X2 in FIG. 4)and radial directions (the directions R1, R2 in FIG. 10). Thethicknesswise direction of the intermediate panel 144 is located inclose proximity to the circumferential directions C1, C2 and is notoriented toward the outer circumferential surface of the stator 22. Theintermediate panel 144 is oriented in this manner for the followingreasons.

If the intermediate panel 144 were disposed along the circumferentialdirections C1, C2 and the axial directions X1, X2, for example, orstated otherwise, if the thicknesswise direction of the intermediatepanel 144 were to lie parallel to the radial directions R1, R2, then theintermediate panel 144 would be disposed more closely to the outercircumferential surface of the stator 22 by the thickness dimensionthereof. In such a case, for insulating the intermediate panel 144 fromthe outer circumferential surface of the stator 22, it is necessary forthe intermediate panel 144 to be spaced away from the outercircumferential surface of the stator 22, which results in an increasein the radial dimensions of the motor 12.

FIG. 11 shows a stator (hereinafter referred to as a “stator 200”),which is illustrated in FIG. 3 of JP 2009-017667 A. The stator 200 shownin FIG. 11 has a lead frame 202, the thicknesswise direction of whichfaces toward the outer circumferential surface of a stator holder 204.Therefore, in order to be insulated from each other, the lead frame 202and the stator holder 204 need to be spaced from each other by arelatively large distance Lc.

In contrast thereto, according to the present embodiment, from thestandpoint of insulating the intermediate panel 144 and the stator 22from each other, since the intermediate panel 144 is disposed along theaxial directions X1, X2 and the radial directions R1, R2, it is possibleto make the distance L1 (FIG. 10) between the intermediate panel 144 andthe outer circumferential surface of the stator 22 shorter. The samefeature holds true for the coil connecting panel 140 and the terminalbase connecting panel 142.

As shown in FIG. 10, according to the present embodiment, each of thefusing members 130 includes the coil connecting panel 140 and theterminal base connecting panel 142, which are staggered along thecircumferential directions C1, C2. Therefore, when a worker or amanufacturing apparatus assembles the terminal base connecting panel 142and thereafter assembles the coil connecting panel 140 in the axialdirection X2, assembly of each of the terminal base connecting panel 142and the coil connecting panel 140 is facilitated, because the respectivemembers do not overlap with each other.

Furthermore, inasmuch as the intermediate panel 144 of the fusing member130 is disposed along the axial directions X1, X2 and the radialdirections R1, R2, the intermediate panel 144 is less likely to overlapwith the terminal base connecting panel 142, thereby facilitatingassembly of the intermediate panel 144. Also, the dimensions of thefusing member 130 are prevented from increasing along thecircumferential directions C1, C2.

(1-3-4-2. Bus Bars 132 a Through 132 c)

FIGS. 12 and 13 are first and second perspective views, respectively, ofthe terminal base 134 with the bus bars 132 a through 132 c assembledthereon. FIG. 14 is a view showing a positional relationship between theterminal base 134 with the bus bars 132 a through 132 c assembledthereon, and the motor housing 28. FIG. 15 is an exploded perspectiveview of the terminal base 134 and the bus bars 132 a through 132 c. FIG.16 is a perspective view of a second cover 182 (insulating cover) withthe bus bars 132 a through 132 c assembled thereon. As shown in FIG. 15,etc., each of the bus bars 132 a through 132 c comprises a plate-likemember (e.g., a copper plate) that is blanked and bent.

As shown in FIG. 15, etc., each of the bus bars 132 a through 132 c hasone end (fusing member connector 160) fastened to the terminal baseconnecting panel 142 of the fusing member 130 by a bolt 148 and a nut150 on the terminal base 134. The other end of each of the bus bars 132a through 132 c (external electric power line joints 162) is fastened tothe terminal 120 of the external electric power line 102 by a bolt 164(FIG. 4) and a nut 166. As shown in FIG. 4, external electric power linejoints 162 of the bus bars 132 a through 132 c, and external electricpower line joints 122 of the terminals 120 of the external electricpower lines 102 are positioned radially inward (along the direction R2)of the outer circumferential surface of the motor stator 22 (or thestator holder 116).

As shown in FIGS. 15 and 16, etc., each of the bus bars 132 a through132 c includes a fusing member connector 160, an external electric powerline joint 162, and an intermediate member 168, although theserespective elements differ in shape from each other.

More specifically, the intermediate member 168 of the bus bar 132 a inthe first phase (e.g., the phase U) basically extends parallel to theaxial directions X1, X2, and further includes a bent portion 170disposed between the fusing member connector 160 and the externalelectric power line joint 162, and a bent portion 172 disposed betweenthe bent portion 170 and the external electric power line joint 162.

The intermediate member 168 of the bus bar 132 b in the second phase(e.g., the phase V) basically extends parallel to the axial directionsX1, X2, and further includes a bent portion 170 disposed between thefusing member connector 160 and the external electric power line joint162, a bent portion 172 disposed between the bent portion 170 and theexternal electric power line joint 122, and a stepped portion 174disposed between the bent portion 172 and the external electric powerline joint 122.

The intermediate member 168 of the bus bar 132 c in the third phase(e.g., the phase W) basically extends parallel to the axial directionsX1, X2, and further includes a stepped portion 174 disposed between thefusing member connector 160 and the external electric power line joint162, and a bent portion 170 disposed between the stepped portion 174 andthe external electric power line joint 122.

Since the respective bus bars 132 a through 132 c are shaped in theforegoing manner, it is possible to maintain the external electric powerline joints 162 in an array parallel to a horizontal plane H, as shownin FIG. 14. As a result, it is easy to connect the bus bars 132 athrough 132 c and the external electric power lines 102 to each other.

The bent portions 170 include bent regions, which are formed byblanking. The bent portions 172 are formed by bending portions of thebus bars 132 a, 132 b in the thicknesswise direction thereof. Thestepped portions 174 are formed by bending portions of the bus bars 132b, 132 c in the thicknesswise direction thereof.

When there is a change in temperature, the bent portions 172 or thestepped portions 174 are flexed to absorb extensions and contractions ofthe bus bars 132 a through 132 c. Therefore, stresses caused in the busbars 132 a through 132 c when the temperature changes are reduced,thereby preventing the bus bars 132 a through 132 c from becomingdamaged.

(1-3-4-3. Terminal Base 134)

The terminal base 134 connects the fusing members 130 and the bus bars132 a through 132 c to each other. As shown in FIG. 15, etc., theterminal base 134 has a first cover 180 that covers a radial outer side(facing in the direction R1) of the fusing members 130, and furtherincludes joints (intermediate joints 178) between the fusing members 130and the bus bars 132 a through 132 c, a second cover 182 that coversportions of the lower surfaces of the bus bars 132 a through 132 c, anda third cover 184 that covers portions of the upper surfaces of the busbars 132 a through 132 c.

As shown in FIGS. 15 and 16, etc., the second cover 182 has prongs 186with teeth 187 thereon. The third cover 184 includes recesses 188defined at positions that are aligned with the prongs 186. As shown inFIG. 13, etc., the second cover 182 and the third cover 184 are coupledto each other when the prongs 186 engage within the recesses 188.

The first cover 180, the second cover 182, and the third cover 184 ofthe terminal base 134 also function as insulating covers for insulatingthe bus bars 132 a through 132 c from surrounding components (the coils112 of the stator 22, etc.). Therefore, the second cover 182 willhereinafter also be referred to as an “insulating cover 182”.

As shown in FIG. 10, etc., the intermediate joints 178 are positionedradially outward (along the direction R1) of the outer circumferentialsurface of the motor stator 22.

Further, as shown in FIG. 10, etc., the coil joints 147 (the jointsbetween the coil ends 114 and the fusing members 130) and theintermediate joints 178 (the joints between the fusing members 130 andthe bus bars 132 a through 132 c) are disposed on circumferentialplanes, portions of which have the same radius. In addition, the coiljoints 147 and the intermediate joints 178 are disposed in positionsthat are mutually staggered circumferentially as viewed from the axialdirection X2.

Therefore, when a worker or a manufacturing apparatus assembles theintermediate joints 178, and thereafter assembles the coil joints 147 inthe axial direction X2, it is easy to assemble each of the intermediatejoints 178 and the coil joints 147, because the intermediate joints 178and the coil joints 147 do not overlap with each other.

FIG. 17 is a perspective view of the insulating cover 182 (second cover182). FIG. 18 is a cross-sectional view, taken along line XVIII-XVIII ofFIG. 16, of the insulating cover 182, at a position where oil dischargeports 190 are not present. FIG. 19 is a fragmentary cross-sectionalview, taken along line XIX-XIX of FIG. 16, of the insulating cover 182,at a position where an oil discharge port 190 is present.

As shown in FIG. 4, etc., the insulating cover 182 is disposed betweenthe outer circumferential surface of the motor stator 22 (or the statorholder 116) and the bus bars 132 a through 132 c at the coil ends 114(in the axial direction X1). The insulating cover 182 also extends alongthe axial direction X2.

As shown in FIG. 18, etc., the insulating cover 182 has a bottom surface192, which is inclined to the horizontal plane H (along the directionsX1, X2 and the directions Y1, Y2), for thereby guiding the oil coolant42 downwardly by gravity.

As shown in FIGS. 17 and 19, etc., the insulating cover 182 haspartition walls 194 for securing the bus bars 132 a through 132 c andfor insulating the bus bars 132 a through 132 c from each other.

As shown in FIGS. 18 and 19, a predetermined gap exists between thelower surfaces of the bus bars 132 a through 132 c and the bottomsurface 192 of the insulating cover 182. Such a gap is created as aresult of the bus bars 132 a through 132 c being fitted in theinsulating cover 182, rather than being insert-molded. The gap may becreated intentionally due to the shapes of the bus bars 132 a through132 c, or may be created due to tolerances. If the bus bars 132 athrough 132 c are insert-molded, then if the bus bars 132 a through 132c were to become deformed due to a change in temperature, a resin thatis held in intimate contact with the bus bars 132 a through 132 c tendsto crack. However, since the gap is present between the bus bars 132 athrough 132 c and the insulating cover 182, the bus bars 132 a through132 c are allowed to become deformed, thereby preventing damage to theinsulating cover 182 due to a change in temperature.

The insulating cover 182 includes the oil discharge ports 190, which aredefined in the bottom surface 192 and extend vertically through thebottom surface 192. The oil discharge ports 190 are positioned atcorners where the bottom surface 192 and the partition walls 194 crosseach other, and in particular, the oil discharge ports 190 are disposedat corners that are positioned relatively on the lower side when theinsulating cover 182 is installed. The oil discharge ports 190 aredisposed on both upper and lower sides of a step that is formed on theinsulating cover 182.

Furthermore, as shown in FIG. 8, etc., the oil discharge ports 190 arespaced adequately from the stator 22 along the axial direction X2, sothat the oil discharge ports 190 do not impair the insulation betweenthe stator 22 and the bus bars 132 a through 132 c.

The oil coolant 42, which is supplied from the side cover 30 to themotor stator 22, may potentially pass through the inside of the stator22 into the terminal base 134. If the oil discharge ports 190 accordingto the present embodiment are not defined in the insulating cover 182,then the oil coolant 42 is likely to be retained on the insulating cover182, thereby increasing the likelihood of a short circuit between thebus bars 132 a through 132 c, and leading to deterioration of theinsulating cover 182.

According to the present embodiment, since the insulating cover 182 hasthe oil discharge ports 190 defined therein, the oil discharge ports 190are effective to prevent the oil coolant 42 from being retained on theinsulating cover 182.

2. Advantages of the Present Embodiment

According to the present embodiment, as described above, the externalelectric power line joint 122 is shifted from the motor stator 22 in theaxial direction X2, and is positioned radially inward (along thedirection R2) of the outer circumferential surface of the stator 22 (seeFIG. 4). Therefore, the dimension of the motor 12 along the radialdirections R1, R2 is reduced by the extent to which the externalelectric power line joint 122 is disposed radially inward (along thedirection R2) of the outer circumferential surface of the stator 22,rather than being disposed radially outward (along the direction R1) ofthe outer circumferential surface of the stator 22.

The junction conductor 104 according to the present embodiment comprisesthe fusing members 130 (coil-side conductors) including the coil joints147, and the bus bars 132 a through 132 c (electric power line-sideconductors), which are separate from the fusing members 130 and includethe external electric power line joint 122. The intermediate joints 178,which interconnect the fusing members 130 and the bus bars 132 a through132 c, are positioned radially outward (along the direction R1) of theouter circumferential surface of the stator 22.

When the stator 22 is assembled on the motor housing 28 in the axialdirection X2, if a portion of the external electric power line joint 122is positioned radially inward (along the direction R2) of the outercircumferential surface of the stator 22, it may be difficult to work onthe external electric power line joint 122 from the axial direction X2.However, according to the above structure, the bus bars 132 a through132 c and the external electric power lines 102 are connected to make upthe external electric power line joints 122, and thereafter, the fusingmembers 130 and the bus bars 132 a through 132 c are connected to makeup the intermediate joints 178, thereby enabling the coils 112 and theexternal electric power lines 102 to be connected to each other.Consequently, assembly of the junction conductor 104 can be simplified.

According to the present embodiment, respective portions of the coiljoints 147 and the intermediate joints 178 are staggered from each otheron circumferential planes, which have the same radius as viewed from theaxial direction X2 (see FIG. 10, etc.). This feature prevents the motor12 from being increased in dimension along the radial directions R1, R2of the motor 12. In addition, since the intermediate joints 178 can beworked on along the axial direction X2, assembly of the fusing members130 is facilitated.

According to the present embodiment, the coil ends 114 of the coils 112project radially outward (along the direction R1). The coil joints 147are made up of the junction conductor 104 and the coil ends 114, whichare connected to each other. The junction conductor 104 includes thebent fusing members 130 (plate-like members). The fusing members 130include the coil joints 147, each of which includes the coil connectingpanel 140 (first planar portion), which extends along the radialdirections R1, R2 and the circumferential directions C1, C2, and theintermediate panel 144 (second planar portion), which is coupled to thecoil connecting panel 140 and extends in the axial direction X2 and theradial direction R1 radially outward (along the direction R1) of theouter circumferential surface of the stator 22 (see FIGS. 7 and 9,etc.).

With the above arrangement, each of the coil connecting panel 140 andthe intermediate panel 144 lies perpendicular to the outercircumferential surface of the stator 22. Therefore, the fusing members130 can easily be spaced from the outer circumferential surface of thestator 22. Accordingly, the insulation between the fusing members 130and the outer circumferential surface of the stator 22 is prevented frombeing lowered. Since the intermediate panel 144 extends in the axialdirection X2 and the radial direction R1, the fusing members 130 areprevented from becoming increased in dimension along the circumferentialdirections C1, C2.

According to the present embodiment, the motor 12 is coupled to one end(i.e., the planet gear 76) of the speed reducer 14, and the externalelectric power line joints 122 are disposed more closely to the speedreducer 14 than the stator 22 along the axial directions X1, X2.Consequently, the external electric power line joints 122 can beinstalled in view of the positional relationship between the externalelectric power line joints 122 and the end of the speed reducer 14. Inview of the layout according to the present embodiment, the dimension ofthe motor 12 along the axial directions X1, X2 can be reduced.

B. Modifications

The present invention is not limited to the above embodiment, butvarious other arrangements may be employed based on the disclosedcontent of the present description. For example, the present inventioncan employ the following arrangements.

1. Objects to which the Present Invention is Applicable

In the above embodiment, the motor 12 is mounted on the vehicle 10.However, the present invention is applicable to other situations inwhich the motor 12 may be employed. For example, although the motor 12is used to propel the vehicle 10 in the above embodiment, the motor 12may be used in other applications in the vehicle 10 (e.g., an electricpower steering system, an air conditioner, an air compressor, etc.).Alternatively, the motor 12 may be used on industrial machines, homeelectric appliances, etc.

2. Motor 12

In the above embodiment, the motor 12 is a three-phase AC motor.However, the motor 12 may be another type of AC motor or a DC motor, forexample, which is cooled by a cooling fluid, or which is of a reducedsize. In the above embodiment, the motor 12 comprises a brushless motor.However, the motor 12 may be a brush motor. In the above embodiment, themotor stator 22 is disposed radially outward (along the direction R1) ofthe motor rotor 20 (see FIG. 1, etc.). However, the motor stator 22 maybe disposed radially inward of the motor rotor 20.

3. Resolver 31

In the above embodiment, the resolver rotor 24 is mounted on the firstprotrusive wall 82. However, the resolver rotor 24 may be fixed toanother member other than the first protrusive wall 82, insofar as theoil coolant 42 is capable of being supplied from the bottom wall 70 ofthe tubular member 52 to the inside of the tubular member 52, or in viewof the structure of the electric power system.

4. Cooling System

[4-1. Cooling Fluid]

In the above embodiment, the oil coolant 42 is used as a cooling fluid.However, rather than the oil coolant 42, another cooling fluid (e.g.,water or the like) may be used from the standpoint of effecting thecooling function. However, in this case, potentially, the other coolingfluid may not be used as a lubricant for lubricating the gear mechanismssuch as the planet gear 76, etc.

[4-2. Tubular Member 52]

In the above embodiment, the planet gear 76, which is coupled to therotational shaft 50, is disposed in the tubular member 52. However, adifferent type of gear mechanism may be disposed in the tubular member52. Alternatively, other members may be disposed in the tubular member52 that are cooled by the cooling medium. For example, a frictionalengagement unit (clutch mechanism), which is coupled to the rotationalshaft 50, may be disposed in the tubular member 52.

By disposing a frictional engagement unit in the tubular member 52, itis possible to reduce the dimension of the motor 12 along the axialdirections X1, X2. Further, in addition to cooling the rotor core 60, italso is possible to cool or lubricate the frictional engagement unit(assuming that the cooling fluid doubles as a lubricating oil).Therefore, as opposed to providing the cooling structure for the rotorcore 60 and the cooling structure for the frictional engagement unitseparately from each other, the structure can be made simpler.

5. Electric Power System

[5-1. Junction Conductor 104]

In the above embodiment, the junction conductor 104 is made up of thefusing members 130 and the bus bars 132 a through 132 c. However, thejunction conductor 104 is not limited to such a structure, insofar asthe terminals 120 of the external electric power lines 102 are disposedradially inward (along the direction R2) of the outer circumferentialsurface of the stator 22, for example. For example, the coil ends 114and the external electric power lines 102 may be connected by either thefusing members 130 or the bus bars 132 a through 132 c.

Furthermore, the shapes of the fusing members 130 or the bus bars 132 athrough 132 c may be changed, insofar as the terminals 120 of theexternal electric power lines 102 are disposed radially inward (alongthe direction R2) of the outer circumferential surface of the stator 22,for example. For example, in the above embodiment (see FIG. 4), althoughthe bus bars 132 a through 132 c basically lie parallel to the axialdirections X1, X2, the bus bars 132 a through 132 c may be inclined tothe axial directions X1, X2. For example, the bus bars 132 a through 132c may be inclined from an upper left position toward a lower rightposition in FIG. 4.

In the above embodiment, the intermediate joints 178, which connect theterminal base connecting panels 142 of the fusing members 130 and thefusing member connectors 160 of the bus bars 132 a through 132 c, aredisposed radially outward (along the direction R1) of the outercircumferential surface of the motor stator 22. However, insofar as theterminals 120 of the external electric power lines 102 are disposedradially inward (along the direction R2) of the outer circumferentialsurface of the stator 22, for example, the intermediate joints 178 mayalso be disposed radially inward (along the direction R2) of the outercircumferential surface of the stator 22.

In the above embodiment, the respective portions of the coil joints 147and the intermediate joints 178 are staggered mutually oncircumferential planes that have the same radius as viewed from theaxial direction X2 (see FIG. 10, etc.). However, insofar as theterminals 120 of the external electric power lines 102 are disposedradially inward (along the direction R2) of the outer circumferentialsurface of the stator 22, for example, the respective portions of thecoil joints 147 and the intermediate joints 178 need not necessarily bedisposed on circumferential planes having the same radius as viewed fromthe axial direction X2.

In the above embodiment, the coil connecting panels 140 of the fusingmembers 130 extend along the radial directions R1, R2 and thecircumferential directions C1, C2, and the intermediate panels 144 arecoupled to the coil connecting panels 140 so as to extend along theaxial direction X2 and the radial direction R1 radially outward (alongthe direction R1) of the outer circumferential surface of the stator 22.However, insofar as the coil ends 114 and the external electric powerlines 102 are connected in such a manner that the terminals 120 of theexternal electric power lines 102 are disposed radially inward (alongthe direction R2) of the outer circumferential surface of the stator 22,for example, the intermediate panels 144 may extend along the axialdirections X2 and the circumferential directions C1, C2, or statedotherwise, the intermediate panels 144 may be disposed parallel to theouter circumferential surface of the stator 22, for example.

In the above embodiment, the motor 12 is coupled to the end of the speedreducer 14, and the external electric power line joint 122 is disposedcloser to the speed reducer 14 than the stator 22 along the axialdirections X1, X2. However, insofar as the coil ends 114 and theexternal electric power lines 102 are connected in such a manner thatthe terminals 120 of the external electric power lines 102 are disposedradially inward (along the direction R2) of the outer circumferentialsurface of the stator 22, for example, the external electric power linejoint 122 may be disposed opposite to the speed reducer 14 across thestator 22 along the axial directions X1, X2.

In the above embodiment, the external electric power line joint 122 isdisposed radially inward (along the direction R2) of the outercircumferential surface of the stator 22. However, insofar as thefunction of the insulating cover 182 can be fulfilled, the externalelectric power line joint 122 may be disposed radially outward (alongthe direction R1) of the outer circumferential surface of the stator 22.

[5-2. Insulating Cover 182]

In the above embodiment, the insulating cover 182 is provided for thebus bars 132 a through 132 c. However, insofar as the terminals 120 ofthe external electric power lines 102 are disposed radially inward(along the direction R2) of the outer circumferential surface of thestator 22, for example, the insulating cover 182 may be dispensed with.If the insulating cover 182 is dispensed with, then the length of thefusing members 130 along the axial direction X2 preferably is increasedin order to provide insulation between the stator 22 and the bus bars132 a through 132 c.

In the above embodiment, the number and layout of the oil dischargeports 190 are as shown in FIGS. 16 and 17. However, insofar as the oilcoolant 42 is capable of being discharged through the oil dischargeports 190, it is sufficient to provide at least one oil discharge port190, and the layout of the oil discharge ports 190 can be changedappropriately.

In the above embodiment, the bus bars 132 a through 132 c extend alongthe axial direction X2 from the outer circumferential side of the stator22. However, the bus bars 132 a through 132 c may be positioned in adifferent location, insofar as insulation can be provided between thestator 22 and the bus bars 132 a through 132 c and the oil coolant 42can be discharged through the oil discharge ports 190. For example, thebus bars 132 a through 132 c may extend radially outward (along thedirection R1) from the outer circumferential surface of the stator 22.Further, the insulating cover 182 may be disposed between the bus bars132 a through 132 c and the outer circumferential surface of the stator22.

In the above embodiment, the insulating cover 182 includes the partitionwalls 194, which are positioned in plural phases between the bus bars132 a through 132 c. However, the partition walls 194 may be dispensedwith, insofar as sufficient insulation can be provided between thestator 22 and the bus bars 132 a through 132 c, and the oil coolant 42can still be discharged through the oil discharge ports 190.

In the above embodiment, the bottom surface 192 of the insulating cover182 is inclined with respect to the horizontal plane H. However, thebottom surface 192 may lie parallel to the horizontal plane H, insofaras sufficient insulation can be provided between the stator 22 and thebus bars 132 a through 132 c, and the oil coolant 42 can still bedischarged through the oil discharge ports 190.

In the above embodiment, the bus bars 132 a through 132 c include thebent portions 172, which are made up of portions of the plate-likemembers that are bent in the thicknesswise direction. The number orlayout of the bent portions 172 may be changed, or the bent portions 172may be dispensed with, insofar as sufficient insulation can be providedbetween the stator 22 and the bus bars 132 a through 132 c, and the oilcoolant 42 can still be discharged through the oil discharge ports 190.

The invention claimed is:
 1. A rotary electric machine comprising: astator including a stator core with coils in respective phases woundthereon; a housing that houses the stator therein; a junction conductorelectrically joining the coils and external electric power lines, whichare disposed outside of the housing, to each other; a rotational shaftformed integrally with a rotor; and same-phase coil joints electricallyconnecting coil ends of the coils in same phases, on one side in adirection of the rotational shaft with respect to the stator core; thejunction conductor further comprising: coil-side joints connected to thesame-phase coil joints on the one side in the direction of therotational shaft with respect to the stator core and radially outward ofthe coils; electric power line joints connected to the external electricpower lines on another side in the direction of the rotational shaftwith respect to the stator core; and a junction extending from the oneside to the other side in the direction of the rotational shaft over theentire stator core and coupling the coil-side joints and the electricpower line joints to each other, wherein at least a portion of theelectric power line joints is positioned radially inward of an outercircumferential surface of the stator with respect to the rotaryelectric machine.
 2. The rotary electric machine according to claim 1,wherein the junction conductor further comprises: coil-side conductorsincluding the coil-side joints; and electric power line-side conductorsincluding the electric power line joints, the electric power line-sideconductors being separate from the coil-side conductors, wherein thecoil-side conductors and the electric power line-side conductors areconnected to intermediate joints, which are positioned radially outwardof the outer circumferential surface of the stator.
 3. The rotaryelectric machine according to claim 2, wherein the coil-side joints andthe intermediate joints have respective portions, which are staggeredmutually on circumferential planes having the same radius as viewedaxially from the rotational shaft.
 4. The rotary electric machineaccording to claim 1, wherein: the coils have coil ends that projectradially outward with respect to the rotary electric machine; thecoil-side joints are made up of the junction conductor and the coilends, which are connected to each other; and the junction conductorincludes bent plate-like members; the bent plate-like members furthercomprising: first planar portions including the coil-side joints, thefirst planar portions being disposed along radial and circumferentialdirections of the rotary electric machine; and second planar portionscoupled to the first planar portions, the second planar portionsextending along axial and radial directions radially outward of theouter circumferential surface of the stator.
 5. The rotary electricmachine according to claim 1, wherein the rotary electric machine iscoupled to one end of a speed reducer; and the electric power linejoints are disposed closer to the speed reducer than the stator in anaxial direction of the rotary electric machine.